I don't see a lot of statistics showing that any form of sex education -- abstinence or contraception -- is a miracle cure-all. Most big urban areas, as far as I can tell, mandate some form of sex education with a contreception focus included and yet they have some of the highest rates of teen pregnancy. I would also imagine that virtually 100 percent of teenagers, regardless of background, know that sexual intercourse can make a baby. Some apparently don't care -- period -- and some apparently let the heat of the moment get in the way.
A lot of us probably have experiences from our youth or college/bar days where hormones got in the way of safe sex, even if the partner was on the pill or IUD and the issue was STDs and not fatherhood.
In some cases kids are raised poorly and don't care about making a baby, in others they were raised "right" but don't care for the 10 minutes or so when the hormones and instinct take over and in others they logically or morally resist the urge and avoid sex or avoid sex without contraception.
charon